Joule Thief breadboard

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    The minimal components of a Joule Thief, which amplifies the 0.5 V input to 2 V or more to drive the red LED. Rather than a toroid core transformer, I used two side-by-side 1 mH inductors.

    1. acmefixer 41 months ago | reply

      Then the only way to get it to oscillate must be through crosscoupling because they are next to each other. That means the chokes should be bound together somehow, most likely with epoxy or silicone glue. The problem with 0.5V supply voltage is that it is too low to start reliably and give enough light from the LED.

    2. hudson 41 months ago | reply

      Yes, cross coupling is going on. The voltage produced varies with the distance between them; a few mm of separation causes a rapid fall off, so it is likely 1/r^2. At 0.5 V it seemed fairly reliable, but would occasionally flicker out. 0.6 to 0.7 V was much more stable.

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